In our U.S. Pat. No. 9,517,491 and which was issued on Dec. 13, 2016, we disclosed a method and apparatus for sorting which has been employed with a great deal of commercial success to address previous problems associated with identifying products within a product stream using multiple optical, and other sensors in a manner which avoids several previously known technical problems. In particular, we described in this patent, previous attempts which have been made to enhance the ability to image objects effectively, in real-time, in view of the known problems associated with the actuation of sensors, and other cameras, in real-time. In the above-identified, and other US patents, we have defined “real-time” as meaning the electrical signal processing which occurs within the span of, and substantially at the same rate as that which is depicted. In the present patent application “real time” may include several micro seconds to a few milliseconds. One of the chief difficulties associated with such efforts to image or view a stream of objects during these time intervals has been that when particular detectors, sensors, and the like, have been previously employed, and then energized, both individually, and in combination with each other, they often have had undesirable effects, and limitations, including, but not limited to, a lack of isolation of the signals of different modes, but which have similar optical spectrums; unwanted changes in the response per optical angle of incidence, and field angle; and/or a severe loss of sensitivity or effective dynamic range of the sensor being employed, among many other issues. Thus the use of many sensors or interrogating means for providing information regarding the objects being sorted, when actuated simultaneously, often destructively interfere with each other thus limiting the ability to identify features or characteristics of an object which would be helpful in classifying it as being either, on the one hand, an acceptable product or object of interest, or on the other hand, an unacceptable one, and which needs to be excluded from the product stream, or perhaps diverted into a different processing stream where it can then be treated, and then later sold, for example, as a different grade of the same product.
While the teachings of this, and other U.S. patents have been quite successful in addressing the myriad of issues surrounding this destructive interference which can arise, and then limit the usefulness of using multiple sensors, cameras, and the like, in sorting devices of assorted designs, developers of this same technology have endeavored to develop an effective means whereby such an apparatus may be optimized to improve an optical contrast generated between the respective objects of interest or products to be inspected, and the surrounding inspection station through which these objects and/or products pass, thereby optimizing the ability for such an apparatus and related methodology to identify both acceptable and unacceptable objects of interest and/or products, and thereby perform more effective sorting of a product stream thus achieving greater benefits for an end user or customer.
A method and apparatus for sorting which avoids the detriments associated with the various prior art teachings and practices utilized, heretofore, is the subject matter of the present application.